Integrated circuit fabrication includes many steps, which may be complex and expensive. For example, one exemplary procedure to form a metal silicide in an integrated circuit includes providing a substrate having a first region and a second region and depositing a first patterned photoresist layer to expose the first region. The first region is doped with a dopant to control resistivity in the first region. Once doping of the first region is complete, the first patterned mask layer is removed and a second patterned mask layer is formed to expose the second region. The second patterned mask layer is a hard mask, such as silicon nitride (SiN). A metal layer, such as nickel (Ni) or the like, is deposited atop the exposed second region and is annealed to form a metal silicide in the exposed second region. Lastly, the second mask layer and any remaining non-silicided metal may be removed after the anneal is complete.
The inventors have provided improved methods to form a metal silicide in an integrated circuit.